Using the arduino digital outputs can someone tell me what circuit I need to switch 24v DC on/off. Each 24V line will only be using 50mA and I have a 24v DC power supply. I need 4 independant channelsor devices to control some pneumatic pilot valves. An RS component code would be a perfect answer.

I know it's a simple electronic question but I'm good with mechanisms rather than the electroncis behind them lol